The Salt Sermon was an oration delivered on June 17, 1838, by Sidney Rigdon in Caldwell County, Missouri. The sermon was a stern condemnation of Mormon dissenters, including Oliver Cowdery, David Whitmer, John Whitmer, and William W. Phelps. At the time, Sidney Rigdon was first counselor in the First Presidency of The Church of Jesus Christ of Latter-day Saints.
According to Rigdon, the dissenters were like the "salt" spoken of by Jesus in a portion of the Sermon on the Mount: "If the salt have lost its savor, wherewith shall it be salted? It is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men." Two days after Rigdon preached the Salt Sermon, eighty Latter-day Saints signed a statement (the so-called Danite Manifesto) warning the dissenters to "depart, or a more fatal calamity shall befall you." The dissenters and their families interpreted these words as threats, and they quickly left Missouri.